A multilayer (or multi-layered) container molded by being punched out from a multilayer structure has a bad outer appearance because an intermediate resin layer is exposed outward on a cut end face of a container. Particularly, in a case of the intermediate resin layer provided with an oxygen absorbing layer, there causes a problem of splashing of iron particles, generation of rust or like because the oxygen absorbing layer contains an iron series metal as a main component.
In order to obviate such problem, in the prior art, there provides a method of covering an end face of the intermediate resin layer such as oxygen absorbing layer by extending the surface resin layer of the multilayer structure so as to turn about on the cut face side (for example, refer to Japanese Unexamined Patent Laid-Open Publication No. HEI 7-227259, No. HEI 11-48385).
In such forming method, male and female cutters (blades) are utilized for punch-out mold, and when the multilayer structure is punched out, the surface resin layer is pulled by hooking the surface resin layer to a blade edge portion to thereby cover the cut end face of the intermediate resin layer.
However, in the prior art method mentioned above, the intermediate resin layer is cut by shearing operation of the male and female cutters, there was a fear that the covering amount may largely vary in accordance with an engaging gap between the blade edge portions of the male and female cutters, and accordingly, in order to eliminate such fear, it is required for a mold to have a high precision.
Furthermore, even in a presence of proper gap, it is extremely difficult to maintain the covering amount because of environmental changes such as ambient temperature, abrasion of the mold in time elapsing, and the like, thus providing a problem that stable quality of products is not expected.
In addition, in the prior art method, the punch-out mold is heated to a temperature approximately to a Vicat softening point of the surface resin layer, which requires a temperature control.
Furthermore, since the multilayer structure is punched out by the shearing operation, burr is formed to the lower end portion of the cut end face, and it is necessary to remove such burr. In a case of large burr, there is a possibility that a portion of the intermediate resin layer exposes outside the covering area of the end face.
Still furthermore, the covering portion of the end face with the surface resin layer extends in the shearing direction of the cut end face as the sheared face, which provides an adverse adhesion to the cut end face. In addition, since the cut end face is cut through the shearing operation, the front end of the end face covering portion is likely hooked and then easily peeled.